they're prepping around knoxville, tennessee. >> we're expecting the worst. you always expect the worst. >> reporter: while the midwest and northeast remain frozen -- >> got 20 layers on. body warmers, hand warmers, foot warmers. >> reporter: a new round of ice and snow is bearing down on 15 states from ohio to alabama. this cold blast, which has taken over one-third of the country, is dangerous. look at what firefighters in chicago had to battle. weapon, that's burning ice. conditions weren't much better for firemen in lawrence, massachusetts. >> it's tough because we're running into frozen hydrants and frozen lines. >> reporter: a plane slipped off this icy runway. at least 11 cities from raleigh to atlanta, to chicago to seattle will have delays. roads are also a mess. icy conditions cause major accidents. >> we can't respond as efficiently as we would, you know, in the summertime. it does pose some obstacles. >> reporter: newark officials got an assist by the mayor, cory booker who moonlights as a superhero. last year, he saved a woman from a fire. this t